Expertise

The general focus at IWW is on microstructure/property relationships in metallic materials, with particular emphasis on light metals based on Al, Mg and Ti. In addition, copper and iron materials are also intensively studied.

The variation of the microstructure is selectively achieved by thermal and thermo-mechanical treatments on the one hand by means of conventional processes such as extrusion, rolling, rotary swaging and wire drawing and on the other hand by means of novel processes of high-grade plastic forming such as Equal Channel Angular Pressing (ECAP) and High Pressure Torsion (HPT). In addition to the microstructure (e.g. grain size and shape, phase morphology and arrangement, type, size and distribution of precipitated phases), the crystallographic texture and in particular the resulting mechanical properties are investigated. Within radiography, not only textures are analyzed, but also residual stress profiles are measured and phase analyses are performed. In terms of mechanical properties, the focus of interest is on strength properties under static loading (creep behavior), quasi-static loading (tension and compression), cyclic loading (fatigue testing) and dynamic loading (notched bar impact testing). Within the scope of these investigations, experiments are also carried out on damping behavior, the behavior of soft magnetic materials, the long-term dimensional stability of materials and the grain refinement of cast materials.

Another focus concerns the improvement of the fatigue behavior by processes of mechanical surface hardening (e.g. shot peening, deep rolling). The altered fatigue behavior is derived from the process-induced property changes at the surface and in areas close to the surface. These include changes in surface topography, surface hardening and residual stress formation, possibly near-surface phase transformations and the crack formation and crack propagation behavior altered by these influencing variables.

Furthermore, the electrochemical corrosion behavior of metallic materials is investigated. This includes, in particular, the study of the corrosion behavior of, for example, copper materials under simultaneous mechanical stress (stress corrosion cracking and fatigue corrosion cracking). The above-mentioned investigation methods, including scanning and transmission electron microscopy, are also used for practice-oriented damage analysis. The findings of the damage analysis are used to derive suggestions for improvements in the use of materials optimized for the particular application.